Tag Archives: origin of life

Credit: American Chemical Society.

Scientists uncover new insights into the origin of life

New research investigated whether early Earth could have supported some of the conditions required for the building blocks of life — as proposed by a famous experiment. Turns out it did.

Credit: American Chemical Society.

Credit: American Chemical Society.

How did we get here? That’s one of the big questions that has been vexing humans probably since we first became conscious. Thanks to the theory of evolution by natural selection, scientists are confident that our species evolved from a common ancestor that we share with other apes alive today. However, Homo sapiens represents a single twig on a branch of the evolutionary tree that reaches back some seven million years. If you follow these branches all the way to the stem, you’ll eventually reach ground zero: the very first lifeform out of which all other life evolved.

Although the Earth is thought to be 4.5 billion years old, the oldest rocks on the record are about 4 billion years old. Not long after this period, tantalizing evidence of life emerges, including 3.7-billion-year-old stromatolites(layered structures created by bacteria) found in Greenland and 4-billion-year-old stromatolites found in the Labrador Peninsula in Canada.

In 1953, chemists Harold Urey and Stanley Miller conducted one of the most famous experiments of the past century, commonly known as the primordial soup experiment. In order to find out how the first signs of life on Earth surfaced, the scientists exposed a mix of gases to a lightning-like electrical discharge to create amino acids. Amino acids are very important because they form proteins, which, in turn, form cellular structures and control reactions in living things. Remarkably, when water, methane, ammonia, and hydrogen — all chemicals present on early Earth — were hit by the simulated lightning, they reacted to form hydrogen cyanide, formaldehyde, and other intermediate molecules that reacted further to generate amino acids, along with other biomolecules.

But some scientists think that this experiment relies on too many things coming together. Early Earth — whose conditions are still rather poorly understood — was wrapped in a hazy atmosphere which would have made it very difficult for lightning and ultraviolet light to reach the planet’s surface.

However, that doesn’t mean that there weren’t other alternative forms of energy that could have jump-started these primordial reactions. Indian researchers at the CSIR-National Chemical Laboratory led by Kumar Vanka wondered if heat from ocean waters — which 4 billion years ago were nearly boiling — might have been one such driving force.

In their experiment, Vanka and colleagues used an ab initio nanoreactor that simulates how mixtures of molecules collide and react, forming new molecules. Their results suggest that ancient ocean heat was enough for hydrogen cyanide and water to mix and form the molecules required to produce the amino acid glycine, as well as the precursors of RNA.

Writing in the journal ACS Central Science, the authors conclude that these reactions are both thermodynamically and kinetically feasible, meaning they do not require a catalyst or a lot of energy.

We might never find out exactly how life first emerged on Earth but the fact that there are multiple pathways that could have given rise to it offers some exciting possibilities. It suggests that maybe the conditions necessary for life to form aren’t all that singular, so perhaps many other planets elsewhere in the galaxy and beyond are blessed with this rare gift.

Example of hydrothermal vent. Credit: Wikimedia Commons.

NASA scientists create basic building blocks of life in a ‘primordial ocean’

Example of hydrothermal vent. Credit: Wikimedia Commons.

Example of a hydrothermal vent. Credit: Wikimedia Commons.

The origin of life is one of the most important questions in science. For NASA, answering this question is especially important because it enables scientists to narrow down their search for alien life, in the solar system or beyond. In a new study, a research team at NASA’s Jet Propulsion Laboratory in Pasadena, California, reported how it managed to create amino acids — the basic building blocks of life that, like pieces of LEGO, assemble into proteins — in an environment that simulates what the ocean floor was like four billion years ago.

Life in a jar

Researchers made miniature seafloors by filling beakers with a solution that mimics Earth’s primordial ocean, including a hydrothermal vent — cracks in the seafloor where hot fluid escapes from the crust. These porous geological structures are produced by chemical reactions between solid rock and water, as alkaline fluids from the Earth’s crust flow up the vent towards the more acidic ocean water. This interaction leads to natural proton concentration differences remarkably similar to those powering all living cells.

Like an underwater chimney, hydrothermal vents produce a warm environment that is constantly in flux, which is why biologists have identified them as a probable hotspot for the formation of life.

“Understanding how far you can go with just organics and minerals before you have an actual cell is really important for understanding what types of environments life could emerge from,” Laurie Barge, and astrobiologist and the first author on the new study, said in a statement. “Also, investigating how things like the atmosphere, the ocean and the minerals in the vents all impact this can help you understand how likely this is to have occurred on another planet.”

Barge and colleagues combined water and minerals, along with pyruvate and ammonia, which are precursor molecules to amino acids. The solution was heated to around 158ºF (70ºC), the average temperature of a hydrothermal vent, and researchers adjusted the pH in order to mimic an alkaline environment. Oxygen was carefully removed until it reached a low concentration, similar to that of early Earth when cyanobacteria had yet to transform the planet’s suffocating atmosphere. Finally, the researchers also added iron hydroxide, also known as “green rust”, which was abundant billion of years ago.

A time-lapse video of a miniature hydrothermal chimney forming in the lab. Credit: NASA/JPL-Caltech.

A time-lapse video of a miniature hydrothermal chimney forming in the lab. Credit: NASA/JPL-Caltech.

The researchers found that the green rust reacted with the oxygen from the solution, producing the amino acid alanine and the alpha hydroxy acid lactate. The latter is important because alpha hydroxy acids are the byproducts of amino acid reactions, and are therefore considered to be essential components of the complex organic molecules that might form life.

“We’ve shown that in geological conditions similar to early Earth, and maybe to other planets, we can form amino acids and alpha hydroxy acids from a simple reaction under mild conditions that would have existed on the seafloor,” said Barge.

Jupiter’s moon, Europa, is believed to hide a deep ocean of salty liquid water beneath its icy shell. Now, a new Nasa study has revealed that this ocean may have an Earth-like chemical balance that could sustain life. Credit: NASA.

Previously, researchers had investigated whether the right ingredients for life could be found in hydrothermal vents or if they could supply enough power to drive important chemical reactions. However, this was the first time that scientists produced the precursors to life in a hydrothermal-vent-like environment.

Such environments are believed to exist elsewhere in the solar system, beneath the thick ice that covers Jupiter’s moon Europa and Saturn’s moon Enceladus. In the future, NASA would like to send robotic exploration missions to these worlds that might drill through the ice and gather evidence of amino acids and other biological signatures.

“We don’t have concrete evidence of life elsewhere yet,” said Barge. “But understanding the conditions that are required for life’s origin can help narrow down the places that we think  could exist.”

The findings appeared in the journal Proceedings of the National Academy of Sciences.

Meteorites may have seeded life in Darwin’s ‘warm little ponds’

How life emerged on Earth is an open question which might never be answered satisfyingly. But that doesn’t mean we aren’t trying. One new study that involved astrophysics, geology, chemistry, biology and other disciplines, found meteorites impacting early Earth billions of years ago could have leached essential elements into warm little ponds. Calculations suggest these basic building blocks assembled into self-replicating RNA molecules that constituted the first genetic code for life on the planet.

primordial soup

Credit: Youtube capture.

Charles Darwin first singled out volcanic pools, or ‘warm little ponds’, as the breeding ground for the first life forms in the 19th century. Darwin once wrote in a correspondence that the chemicals found such ponds closely resemble the cell’s composition of its cytoplasm.

“But if (and oh what a big if) we could conceive in some warm little pond with all sorts of ammonia and phosphoric salts, light, heat, electricity etcetera present, that a protein compound was chemically formed, ready to undergo still more complex changes [..] ”

~Charles Darwin, in a letter to Joseph Hooker (1871)

The other competing theory is that life emerged in hydrothermal vents in the deep sea, which some scientists believe are the most conducive environments for nascent life.

Primordial soup

Schematic of the various physical and chemical changes which would have eventually led to the first life forms. Credit: McMaster University.

Schematic of the various physical and chemical changes which would have eventually led to the first life forms. Credit: McMaster University.

Scientists at McMaster University and the Max Planck Institute in Germany claim life originated sometime between 3.7 and 4.5 billion years ago with the help of meteorites. In their new study, the team found that what sparked life were essential components of nucleotides which were delivered by cosmic objects. Their simulations suggest that if these building blocks reached a high enough concentration in pond water, these could bond together as the water level rose and fell through frequent cycles of precipitation, evaporation, and drainage. Early Earth was constantly battered by meteors, so those were certainly not in low supply.

[Also Read: New evidence indicates that life on Earth emerged almost 4 billion years ago]

Eventually, these favorable conditions led to the creation of RNA polymers, which are similar to DNA in the sense that both carry genetic information. The researchers’ calculations suggest that in time some of these chains folded over and spontaneously replicate themselves by drawing other nucleotides from their environment. Replication is an essential prerequisite for the definition of life.

“No one’s actually run the calculation before,” says lead-author Ben K.D. Pearce of McMaster’s Origins Institute and its Department of Physics and Astronomy. “This is a pretty big beginning. It’s pretty exciting.”

“Because there are so many inputs from so many different fields, it’s kind of amazing that it all hangs together,” said lead-author Ralph Pudritz, also at McMaster. “Each step led very naturally to the next. To have them all lead to a clear picture in the end is saying there’s something right about this.”

According to the authors, these favorable conditions would have been present in thousands of ponds across the planet. They reckon the key combinations of essential building blocks for life were far more likely to have occurred in such ponds than in hydrothermal vents. Specifically, both wet and dry cycles are required to form RNA, the scientists wrote in the Proceedings of the National Academy of Sciences. 

Life may have first appeared in warm little ponds such as the one pictured here on the Bumpass Hell trail in Lassen Volcanic National Park in California. Credit: Ben K.D. Pearce, McMaster University.

Life may have first appeared in warm little ponds such as the one pictured here on the Bumpass Hell trail in Lassen Volcanic National Park in California. Credit: Ben K.D. Pearce, McMaster University.

Besides meteorites, some have suggested earlier that space dust may have also seeded life-generating nucleotides. The newly published paper found that while such space dust can indeed carry the right elements, it can not deposit them in sufficient concentration to generate life.

“We’re thrilled that we can put together a theoretical paper that combines all these threads, makes clear predictions and offers clear ideas that we can take to the laboratory,” Pudritz says.

Before anyone gets overly excited, as Pudritz mentions, this is a ‘theoretical paper.’ Speaking to New Scientist, John Sutherland of the MRC Laboratory of Molecular Biology in Cambridge, UK, has identified various shortcomings of the study. One would be that the organic material required to seed life and present in meteorites will atomise on impact with Earth. Sutherland also claims that it was experimentally shown years ago that linking together nucleobases and ribose won’t produce RNA.

Artist impression of early Earth atmosphere. Credit: Peter Sawyer.

Experiment mimicked Earth’s early atmosphere hit by extraterrestrial impact. It produced all four RNA bases

Artist impression of early Earth atmosphere. Credit: Peter Sawyer.

Artist impression of early Earth atmosphere. Credit: Peter Sawyer.

Researchers from France and the Czech Republic put a spin on a seminal science experiment that recreates the conditions necessary for life to appear. They mimicked Earth’s early atmosphere as it was impacted by cosmic bodies like meteorites and found the interaction produced all the four based of RNA, which is chemically related to DNA and just as essential to life. The findings support the RNA World and the Origins of Life hypothesis, according to which RNA stored both genetic information and catalyzed the chemical reactions in primitive cells.

Back in the 1950s, two biochemists named Stanley Miller and Harold Urey sealed a mixture of gases that modeled Earth’s early atmosphere as scientists assumed it must have been like at the time, then zapped electricity through the brew. The experiment showed that several organic compounds could be formed spontaneously this way from inorganic compounds, including amino acids — which are the building blocks of proteins.

The Miller-Urey experiment was a total hit and the findings traveled the global instantly, as it was the first study to add some tangible evidence to the theory that life first appeared spontaneously.

Schematic of the Miller-Urey experiment.

Schematic of the Miller-Urey experiment.

As years past, however, the Miller-Urey experiment passed out of favor among scholars, though to this day it’s one of the most widely enacted experiments in high schools and universities around the world. Fred Hoyle, an astrophysicist, once compared the likelihood of life appearing on Earth by chemical reactions “as equivalent to the possibility that a tornado sweeping through a junkyard might assemble a Boeing 747 from the materials therein”. Critics have argued that even though amino acids can provide the necessary primitive biochemistry for proteins to form, you need more than just proteins to activate a cell’s catalytic chemistry. Miller and Urey couldn’t have known at the time, but both RNA and DNA seem to be heavily involved in biochemistry.

Another problem with the Miller-Urey experiment was that it assumed Earth’s early atmosphere was ‘reducing’, the opposite of today’s ‘oxidizing’ one. Since then, researchers now largely presume our planet’s early atmosphere was neutral, somewhere in between reducing and oxidizing.

But this textbook experiment isn’t done yet. Researchers gave a new spin on the experiment to add something Miller and Urey hadn’t originally considered: impacts from cosmic bodies, an extremely common occurrence on primordial Earth.

In the new study, the researchers argued that Earth’s atmosphere from 3.6 billion years ago was a bit on the reducing side, which is somewhat different from the atmosphere used by Millet-Urey but still relevant. The aim of the study was to monitor the gases for formamide, a compound made of carbon, nitrogen, and oxygen, with hydrogen in between. Previously, research showed that under the right conditions, formamide can react with itself to produce all the four RNA bases.

To mimic the shockwaves produced by an extraterrestrial impact, the researchers turned to the Prague Asterix Laser System which can generate Terawatt-sized pulses. The shock waves caused chemical reactions that went on to form formamide and, eventually, all the four RNA bases, albeit in minute quantities — barely above the detectable limit, but that’s Ok since a real impact would have been much more powerful.

“We show that RNA nucleobases are synthesized in these experiments, strongly supporting the possibility of the emergence of biologically relevant molecules in a reducing atmosphere. The reconstructed synthetic pathways indicate that small radicals and formamide play a crucial role, in agreement with a number of recent experimental and theoretical results,” the team wrote.

The findings published in PNAS support the RNA World theory, which posits bacterial cells cannot form from nonliving chemicals in one step. Instead, there must be intermediate forms, “precellular life,” and RNA is the leading contender because it has the ability to act both as an enzyme and encode genes. This offers a way around the “chicken-and-egg” problem (Genes require enzymes; enzymes require genes). While the sort of atmosphere assumed by the study is debatable, it’s exciting to hear about a plausible route for producing the basic building blocks of RNA and life eventually.

[via ArsTechnica]

 

Early Earth wasn’t the most hospitable place in the Universe, but some in all this chaos life emerged. Image credit: Peter Sawyer / Smithsonian Institution.

‘Primordial soup’ theory doesn’t hold up, study says. Instead, life might have first emerged elsewhere

Early Earth wasn’t the most hospitable place in the Universe, but some in all this chaos life emerged. Image credit: Peter Sawyer / Smithsonian Institution.

Early Earth wasn’t the most hospitable place in the Universe, but some in all this chaos life emerged. Image credit: Peter Sawyer / Smithsonian Institution.

For nearly nine decades, science’s favorite explanation for the origin of life has been the “primordial soup”. This is the idea that life began from a series of chemical reactions in a warm pond on Earth’s surface, triggered by an external energy source such as lightning strike or ultraviolet (UV) light. But recent research adds weight to an alternative idea, that life arose deep in the ocean within warm, rocky structures called hydrothermal vents.

A study published last month in Nature Microbiology suggests the last common ancestor of all living cells fed on hydrogen gas in a hot iron-rich environment, much like that within the vents. Advocates of the conventional theory have been sceptical that these findings should change our view of the origins of life. But the hydrothermal vent hypothesis, which is often described as exotic and controversial, explains how living cells evolved the ability to obtain energy, in a way that just wouldn’t have been possible in a primordial soup.

Under the conventional theory, life supposedly began when lightning or UV rays caused simple molecules to join together into more complex compounds. This culminated in the creation of information-storing molecules similar to our own DNA, housed within the protective bubbles of primitive cells. Laboratory experiments confirm that trace amounts of molecular building blocks that make up proteins and information-storing molecules can indeed be created under these conditions. For many, the primordial soup has become the most plausible environment for the origin of first living cells.

But life isn’t just about replicating information stored within DNA. All living things have to reproduce in order to survive, but replicating the DNA, assembling new proteins and building cells from scratch require tremendous amounts of energy. At the core of life are the mechanisms of obtaining energy from the environment, storing and continuously channelling it into cells’ key metabolic reactions.

Did life evolve around deep-sea hydrothermal vents?
U.S. National Oceanic and Atmospheric Administration/Wikimedia Commons

Where this energy comes from and how it gets there can tell us a whole lot about the universal principles governing life’s evolution and origin. Recent studies increasingly suggest that the primordial soup was not the right kind of environment to drive the energetics of the first living cells.

It’s classic textbook knowledge that all life on Earth is powered by energy supplied by the sun and captured by plants, or extracted from simple compounds such as hydrogen or methane. Far less known is the fact that all life harnesses this energy in the same and quite peculiar way.

This process works a bit like a hydroelectric dam. Instead of directly powering their core metabolic reactions, cells use energy from food to pump protons (positively charged hydrogen atoms) into a reservoir behind a biological membrane. This creates what is known as a “concentration gradient” with a higher concentration of protons on one side of the membrane than other. The protons then flow back through molecular turbines embedded within the membrane, like water flowing through a dam. This generates high-energy compounds that are then used to power the rest of cell’s activities.

Life could have evolved to exploit any of the countless energy sources available on Earth, from heat or electrical discharges to naturally radioactive ores. Instead, all life forms are driven by proton concentration differences across cells’ membranes. This suggests that the earliest living cells harvested energy in a similar way and that life itself arose in an environment in which proton gradients were the most accessible power source.

Vent hypothesis

Recent studies based on sets of genes that were likely to have been present within the first living cells trace the origin of life back to deep-sea hydrothermal vents. These are porous geological structures produced by chemical reactions between solid rock and water. Alkaline fluids from the Earth’s crust flow up the vent towards the more acidic ocean water, creating natural proton concentration differences remarkably similar to those powering all living cells.

The studies suggest that in the earliest stages of life’s evolution, chemical reactions in primitive cells were likely driven by these non-biological proton gradients. Cells then later learned how to produce their own gradients and escaped the vents to colonise the rest of the ocean and eventually the planet.

While proponents of the primordial soup theory argue that electrostatic discharges or the Sun’s ultraviolet radiation drove life’s first chemical reactions, modern life is not powered by any of these volatile energy sources. Instead, at the core of life’s energy production are ion gradients across biological membranes. Nothing even remotely similar could have emerged within the warm ponds of primeval broth on Earth’s surface. In these environments, chemical compounds and charged particles tend to get evenly diluted instead of forming gradients or non-equilibrium states that are so central to life.

Deep-sea hydrothermal vents represent the only known environment that could have created complex organic molecules with the same kind of energy-harnessing machinery as modern cells. Seeking the origins of life in the primordial soup made sense when little was known about the universal principles of life’s energetics. But as our knowledge expands, it is time to embrace alternative hypotheses that recognise the importance of the energy flux driving the first biochemical reactions. These theories seamlessly bridge the gap between the energetics of living cells and non-living molecules.

Arunas L Radzvilavicius, , UCL

This article was originally published on The Conversation. Read the original article.

Pleasant thought of the Day: the galaxy may be a graveyard full of dead aliens

As astrobiologists continue to find that the basic building blocks of life are littered throughout space, and how easy it seems for complex organic molecules, like amino acids and nucleic acids, to assemble given conditions thought to be prevalent on many worlds throughout the cosmos, the question as to why we haven’t detected life outside of the earth becomes more and more curious. Where are all the aliens? Why haven’t we seen or heard their signals from space? Could we really have been the only planet where life evolved?

Artistic representation of a superhabitable planet.

Artistic representation of a superhabitable planet.

A team of astrobiologists, lead by Dr. Aditya Chopra from The Australian National University (ANU) thinks there may be an answer to these difficult questions, and you may want to take a seat before I give you the news. I’m sorry to have to break it to you like this, but the aliens, well, they didn’t make it.

According to an article published by the team at ANU in the January 2016 issue of Astrobiology, life probably does arise very frequently on planets throughout the galaxy. Life is tough, in the sense that it is easy to get started in environments all over the place, but ironically it is also very brittle, in the sense that to hang on and evolve, its environment has to be very supportive. Dr. Chopra says, “Early life is fragile, so we believe it rarely evolves quickly enough to survive.”

If true, then most life that has arisen in the cosmos is dead! We’re not talking advanced civilizations that destroyed themselves with nuclear war or unleashed the robot apocalypse, we’re talking about the earliest development of life, simple cells, or possibly even porto-cells, that seemed to just be getting started then, wham, environmental catastrophe shuts them down while they’re still vulnerable, inefficient replicators, without much time to have evolved more robust survival features. If the most primitive life forms emerge often, but survive infrequently, then the evolution of very complex and intelligent life will also be very infrequent. The very low probability for survival beyond these most primitive stages is known as the Gaian Bottleneck.

The Gaian Bottleneck may be a type of filter that weeds out a lot of hopeful little worlds creating an essentially barren universe. Somehow earth made it through the Gaian Bottleneck. Earth must have had conditions not only for jump-starting life, but for providing a more stable environment that allowed further evolution of that life. If given the chance, the ANU team believes that life then begins to form feedback loops with the planet that help stabilize it, making it even more habitable for the long haul. Dr. Charley Lineweaver, also of the ANU team commented that, “Early microbial life on Venus and Mars, if there was any, failed to stabilize the rapidly changing environment. Life on Earth probably played a leading role in stabilizing the planet’s climate.”

So the next time life seems to be treating you unfair, look up at the stars and think of all the little aliens that never even had a real shot in this great big cold universe, and maybe it will help to know that you come from a long line of tough survivors.

origin_of_life

Origin of life a fluke? Study suggests more’s at play than just randomness

origin_of_life

(c) University of Texas

One of the greatest mysteries scientists have been trying to reveal is how inanimate chemicals  joined  to produce life. It’s definitely one of the biggest questions scientists are trying to answer, and the challenges are numerous since it’s very difficult to appreciate what the exact conditions necessary for this to happen were billions of years ago. We might never find out what the exact molecules that sprouted life were, but by studying the biomolecules available today, valuable clues emerge. In time, it may be possible to simulate and re-create these conditions.

Pasquale Stano at the University of Roma Tre sought to investigate how biomolecules might have provided one way to trigger life trough a characteristic process known to scientists since the 1980s: self-organization. Previously, a model for the origin life was devised into  a two-stage process of natural chemical evolution:
      1) formation of organic molecules, which combine to make larger biomolecules;
      2) self-organization of these molecules into a living organism.

The simplest “living system” we can imagine, involving hundreds of components interacting in an organized way to achieve energy production and self-replication, would be extremely difficult to assemble by undirected natural process.  And all of this self-organization would have to occur before natural selection (which depends on self-replication) was available, according to Craig Rusbult. Basically, the complexity required for life (the two stage process) is a lot greater than the complexity available by natural process, considering lifeless matter is the starting point. With this in mind, scientists have been trying to devise new models with less requirements while still being viable – no such model has been found thus far, and some believe life as we know it originated as a fluke of nature.

We’re missing something

origin of life lipids liposomes

(C) University of Roma Tre

Stano’s research suggests that we simply don’t know all the variables yet and our model assumptions might be wrong from the get-go. University of Roma scientists chose an assembly comprised of 83 different molecules including DNA, which was programmed to produce a special green fluorescent protein (GFP) that could be observed under a confocal microscope. This assembly can produce proteins, necessary for the formation of life.

To produce proteins, all of these molecules need to be really close together for chemical reactions to occur, which is why cell components are so densely packed together. The researchers diluted the assembly with water, spacing the molecules apart and making protein generation impossible. However, they then added a chemical called POPC; a fatty molecule which isn’t soluble in water and when in contact with water forms liposomes. These have a very similar structure to the membranes of living cells and are widely used to study the evolution of cell. This was made in hope that some of these liposomes would trap the myrriad of molecules required for assembly. Here’s where it gets interesting.

[RELATED] Origin of life needs some serious rethinking 

A computer simulation showed that the chance of even one liposome producing the green fluorescent protein the assembly was programmed for is zero. In their experiment, however, the scientists found that five in every 1,000 such liposomes had all 83 of the molecules needed to produce the protein and glowed in the dark. Stano and colleagues do not yet understand why this happened, but what’s certain is that their model assumptions were wrong and that something unique may be at play.

It may be that these particular molecules are suited to this kind of self-organisation because they are already highly evolved, which is why research into origin of life is so difficult. Research which less complex molecules will follow next to see if the results can be replicated. Nevertheless, their findings described in the journal Angewandte Chemie  provide one more clue and a solid stepping stone for researchers to follow in their quest to answer how life on Earth came to be.

Darwin was proven right by study: life originated on earth, not in the sea

Life on Earth started out in a ‘small little pond’, just like Darwin, the father of evolution, proposed more than 140 years ago, according to a provocative new study.

According to this study, the primordial cells were ‘created’ (though germinated would be a better word) in pools of condensed vapor which appeared as a result of hot water or steam bubbling towards the surface. The finding, which was published in the Proceedings of the National Academy of Sciences challenges the ‘traditional’ view that life originated in the sea, supporting the first true theory of life origin – Darwin’s.

To come to this conclusion, researchers analyzed some key chemical markers in rocks and ancient inland and marine habitats and compared them with a genetic reconstruction of Earth’s first inhabitants. Physics Professor Dr Armen Mulkidjanian, leader of the study, discovered that oceans did not have the right balance of elements to foster life, and instead, found the perfect balance for a ‘hatchery’ inland, especially in places like hot springs and geysers, or where volcanic activity can actively vent hot vapors from beneath the surface.

Researchers noted that these ‘cradles of life’ share all the advantages of the deep sea environment, and also have one crucial advantage: the presence of organic matter. Other scientists seem quite convinced by this study. Prof Mulkidjanian, of Osnabruck University in Germany:

‘I do not think the oceans were a favourable environment for the origin of life – freshwater ponds seem more favourable,’ Nobel laureate Jack Szostak at Harvard University told New Scientist.
‘Freshwater ponds have lower salt concentrations, which would allow for fatty acid based membranes to form.’

Basically similar to Darwin’s idea, this model suggests that life originated on earth and then quickly migrated to the sea. As Darwin put it in a legendary letter to English botanist Joseph Hooker, life may have begun in a ‘a warm little pond’. He then writes:

‘Geochemical reconstruction shows the ionic (chemical) composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapour-dominated zones of inland geothermal systems. ‘The pre-cellular stages of evolution might have transpired in shallow ponds of condensed and cooled geothermal vapour that were lined with porous silicate minerals mixed with metal sulfides and phosphorous compounds.’

Who said Darwin couldn’t teach us anything new?